The plasma membrane is the only membrane present in lens fiber cells and human erythrocytes. This observation has permitted extensive characterization of membrane composition and organization in the erythrocyte, but has surprisingly not been fully exploited in the study of plasma membrane from lens fiber cells. Morphological analyses have clearly demonstrated the involvement of lens fiber cell membrane in human cataractogenesis; and it is highly possible that changes in membrane composition and organization may be the initiating event in the formation of cataracts. The biochemical role of membrane proteins in these changes, however, is unknown because of a lack of fundamental knowledge concerning membrane protein composition and organization. To this end, intrinsic membrane proteins will be identified and antisera made against these components will be used in conjunction with bifunctional crosslinking reagents to determine their nearest-neighbor, noncovalent interactions. These studies will elucidate the identity and stoichiometry of protein interactions in both purified membrane preparations and intact lens fiber cells from bovine and normal human lenses. Analogous studies will be conducted with human cataractous lenses. Major emphasis will be placed upon monospecific antisera, peptide mapping and crosslinking reagents as probes of compositional and organizational changes during cataractogenesis. Together, these studies will provide basic information of membrane protein composition and organization, from which the role of these proteins in human cataractogenesis will be investigated.